Pressure feeding apparatus for a gear honing machine



Jan. 23, 1962 K. J. DAVIS 3 7,7 8

PRESSURE FEEDING APPARATUS FOR A GEAR HONING MACHINE Filed June 1, 1959 3 Sheets-Sheet l INVENTOR.

3 Sheets-Sheet 2 K. J. DAVIS PRESSURE FEEDING APPARATUS FOR A GEAR HONING MACHINE r- 1' illiltjj; .211;

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Jan. 23, 1962 Filed June 1, 1959 ATTORNE S Jan. 23, 1962 K. J. DAVIS 3,017,723

PRESSURE FEEDING APPARATUS FOR A GEAR HONING MACHINE Filed June 1, 1959 5 Sheets-Sheet 5 INV EN TOR FIG.5.

3,917,728 PRIEUIIE FEEDHNG APPARATUS FUR A GEAR HUNENG MAUHENE Kenneth J. Davis, Detroit, Mich, assignor to National Breach dz Machine Company, Detroit, Mich a corporation of Michigan Filed June It, 1959, Ser. No. 817,405 16 Claims. (CL 51-465) The present invention relates to pressure feeding apparatus for a gear honing machine.

It is an object of the present invention to provide means for effecting relative radial feed between a gear and gearlike hone under a controlled pressure.

More specifically, it is an object of the present invention to provide pressure feed control means comprising a weighted cam slide and friction surfaces effective to oppose movement of the slide with a force variable in accordance with applied pressure between the gear and hone.

t is a further object of the present invention to provide pressure feed control means including an irreversible cam device and yieldable means connecting said device to a movable support for a gear or gear-like hone.

It is a further object of the present invention to provide pressure feed control means comprising a weighted cam slide, a cam follower, and means preferably including a yieldable force limiting device adapted to connect said cam follower to a movable support for a gear or gear-like hone.

It is a further object of the present invention to provide pressure feed control means as described in the preceding paragraph comprising means for limiting the speed of movement of said cam slide to eliminate inertia effects.

It is a further object of the present invention to provide a frictionally controlled weighted cam slide including vertically movable abutment means, and means for moving said abutment means upwardly to move a gear or hone support to an inoperative position and movable downwardly at a slow controlled rate to move the support to provide application of a predetermined operating pressure in which inertia effects are eliminated.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings, illustrating a preferred embodiment of the invention, wherein:

FIGURE 1 is a front elevation of a gear honing machine to which the present invention is applied.

FIGURE 2 is a side elevational view of the gear honing machine.

FIGURE 3 is an enlarged elevational view of the pressure feed control mechanism with parts broken away.

FIGURE 4 is an elevational view of the device shown in FIGURE 3 as seen from the left thereof.

FIGURE 5 is an elevational view of the device shown in FIGURE 3 as viewed from the rear thereof.

FIGURE 6 is a plan view of the pressure feed control mechanism.

The present invention relates to the field of gear honing in which a gear-like honing tool is operated in mesh, preferably at crossed axes, with a work gear which may have been hardened by suitable heat treatment. The honing tool is formed of a solid resin such for example as a suitable epoxy resin having abrasive particles embedded therein and exposed at the surfaces of the teeth. The operation is carried out by driving either the gear or the hone in rotation and driving the other of the members as a result of their meshed engagement. A relative traverse, preferably in a direction parallel to the axis of the gear, is provided.

In gear honing as carried out by apparatus including tae atent and the present invention, the operating pressure between the teeth of the gear and hone is the result of radial forces acting between the gear and hone. In some cases these radial forces may be continued during the honing operation by continuous application of pressure. In other cases the gear and hone may be brought into a predetermined accurately controlled initial pressure contact after which the members are maintained at exact center distance. It will of course be appreciated that as honing continues in the second case the radial pressure between the gear and hone is reduced.

Referring now to FIGURES 1 and 2 there is shown a gear honing machine comprising a base 10 on which are mounted head and tailstocks indicated generally at 3.2 and lidrespectively, the headstock including a center I6 adapted to be advanced axially toward a center 18 in the tailstock so as to support a work gear therebetween. Suitable means such for example as an air cylinder 20 is connected by an arm 22 to effect axial movement of the center 16.

Mounted on the base 10 is a column 24- on which is supported a hone drive assembly 26. The hone drive assembly 26 is angularly adjustable about ahorizontal axis intersecting the axis of the hone so that the entire hone drive assembly and hone may be adjusted to position the hone in a desired crossed axes relationship with respect to a work gear. The hone drive assembly 26 is piloted on the column 24 and is adapted to be clamped in adjusted position by screws indicated at 32 which are associated with arcuate T-slots.

The hone drive assembly includes a hone head 34 which is movable relative to the remainder of the hone drive assembly on suitable rectilinear support means (not shown). The direction of movement of the hone head 34 is directly toward and away from the axis of a work gear as established by the centers i6, 18. The drive connection between the motor Stl and the hone 28 includes a suitable universal connection which permits the hone to be driven from the motor 30, while being adjusted perpendicularly to its axis.

The present invention is concerned with the mechanism for effecting movement of the hone head 34 and includes structure located within the column 24 and illustrated in FI URES 3-6. As best seen in FIGURE 3, the hone head has projecting from the rear thereof a headed stud 3-5 for connection to the pressure control feed mechanism.

The pressure control feed mechanism derives its actuating force from weights 38 seen in FIGURE 2, which are received within a housing 4t and which are carried at the upper end of a vertically movable cam rod 42. The cam rod 42, as best illustrated in FIGURE 3, i provided adjacent its lower end with a slightly inclined cam surface 44 engageable by a cam follower in the form of a roller 4-6 carried by a rocker body 48 pivoted as indicated at 5% to the pressure feed control frame 52. Adjacent its lower end the cam rod 42 includes a more abruptly and oppositely inclined cam surface 54 engageable by a cam follower in the form of a second roller 56 also carried by the rocker body 43.

The means for connecting the rocker body 48 to the hone head 34- comprises a bracket 58 to which is con nected a dog at having a dogging point 62 adapted to engage behind the head 64 of the stud 36.

Connected to the rocker body 43 is a leaf spring 66 the upper portion of which is cut away as indicated at es. The lower portion of the leaf spring is connected by bolts '71 to the rocker body and the leaf spring may be adjusted vertically. it will be apparent that in the rela tionship illustrated in FIGURE 3 the leaf spring is adapted to transmit forces to the stud 36 tending to move the stud to the right, and correspondingly is adapted to yield under excessive forces tending to move the hone head 34- to the left. In the illustrated condition the head of the stud is engaging the extreme free end of the leaf spring and hence the spring will yield under a minimum force for which the leaf spring is designed. If the leaf spring is bodily adjusted upwardly, the force under which it will yield increases and upward adjustment may be continued to a point where a solid portion of the leaf spring underlies the head of the stud 36.

The cam rod 42 is supported in an elongated bushing 72 which determines the frictional resistance to vertical movement of the cam rod. It will be appreciated that when negligible or limited transverse pressure is applied to the cam rod by the roller cam follower 46, frictional resistance to downward movement of the cam rod is negligible. However, when the inclined surface 44 of the cam rod moves the roller 46 and rocker body 48 so as to apply a pressure between the gear and hone, the cam rod is urged to the left as seen in FIGURE 3 and downward movement of the cam rod is thus opposed by friction developed between the bushing 72 and the cam rod 42. This frictional resistance to movement of the cam rod under varying amounts of lateral thrust established by the roller 46 counterbalances a large and definite proportion of the force applied by the weights 38 so that the lateral thrust applied between the gear and hone may be predetermined with considerable accuracy.

Purely by way of example, a series of weights totalling about 30 pounds, may be efifective to produce a radial force acting between the gear and hone on the order of 50-100 pounds. This is true even though the inclination of the cam surface 44 is extremely high, since the frictional resistance to downward sliding movement of the cam rod 42 in the bushing 72 exerts a controlling influence.

The bushing 72 is slotted to permit the nose of a guide screw 74 to enter a slot 76 formed in the cam rod which prevents rotation of the cam rod and maintains the fiat inclined cam surface 44 always in position to cooperate with the cam follower roller 46. The bushing is of course cut away as indicated at 78 to expose the side of the cam rod for engagement by the roller 46.

In addition, a spring pressed plunger 80 is provided and extends through an opening 82 in the bushing to engage a side of the cam rod 42. By this means a separate independently adjustable lateral friction regulating device is provided.

From the foregoing construction it will be apparent that the horizontal force applied to the hone head urging a hone carried thereby into engagement with a work gear may be accurately controlled. In the first place the output of the pressure control feed mechanism may be varied by varying the individual weights 38 applied to the upper end of the rod. Secondly, the friction opposing vertical movement of the rod may be varied by appropriate adjustrnent of the spring pressed plunger 80.

An important feature of the present invention is the provision of means to eliminate the effect of inertia in mechanism. It will be appreciated that if movement of the hone head to operating position was permitted to take place relatively freely inertia of the solid mass of individual weights 38 would result in an uncontrolled and normally relatively greater force than is desired. Accordingly, means are provided for effecting a slow gradual controlled descent of the cam rod 42 to the position in which its further downward movement is prevented by a buildup of frictional resistance to motion dependent upon an increase in lateral transverse pressure between the rod and the bushing 72. This means comprises a motor 90 connected by suitable transmission means to a pinion 92 in mesh with a gear 94. The gear 94 is pinned to a shaft 96 carrying a cam 98, the outline of which is best seen in FIGURE 4. The cam 98 engages a cam follower in the form of a roller 100 carried by a control lever 102 pivoted to a pin 104 carried by the frame 52.

motor with the rounded end 108 of the lever 102 either in its extreme upward position or its extreme lowered position. The motor operates at low speed and is geared down by the ratio of the pinion and gear set 92, 94 so that downward movement of the cam rod 42 takes place very slowly so as to avoid building up momentum and causing an inertia effect on the infeed of the hone relative to the gear.

After a honing cycle has been completed the motor 90 is energized to complete a half turn of the cam 98 to move the cam rod 42 upwardly. Upward movement of the cam rod causes engagement of the relatively abrupt cam surface 54 and the roller 56 to rock the rocker body 48 counterclockwise as seen in FIGURE 3 and thereby to move the hone head 34 to the left, a direction of movement which separates the hone from a work gear.

The use of the gravity operated cam rod provides irreversible means for applying a continuous feeding force of a predetermined constant value to the hone. As previously stated, the hone head may be locked against further movement during the honing operation, but if this means is not applied the hone is adapted to follow up as material is removed from a work gear. However, if eccentricity exists in a work gear, the creation of dangerously high pressures between the gear and hone is avoided by the use of the leaf spring 68 which may be set to yield so as to limit the forces developed between the teeth of the gear and hone to safe values.

The drawings and the foregoing specification constitute a description of the improved pressure feeding apparatus for a gear honing machine in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

1. In a machine tool, a base, a work support, a tool support, means on said base mounting one of said supports for movement toward and away from the other, motive means for applying an accurately controlled force to said one support for determining the pressure between a work piece and tool carried by said supports, said motive means comprising a housing fixed to said base, a friction bushing in said housing, a cam rod slidable in said bushing, means for applying a constant bias to said rod to urge said rod axially, a cam on said cam rod, a cam follower engaging said cam and movably mounted on said housing, coupling means to connect said cam follower to said one support, and motor actuated abutment means operated to release said rod for slow longitudinal movement.

2. In a machine tool, a base, a work support, a tool support, means on said base mounting one of said supports for movement toward and away from the other, motive means for applying an accurately controlled force to said one support for determining the pressure between a work piece and tool carried by said supports, said motive means comprising a housing fixed to said base, a vertical friction bushing in said housing, a vertical weighted cam rod slidable in said bushing, a cam on said rod, a cam follower engaging said cam and movably mounted on said housing, coupling means to connect said cam follower to said one support, and motor actuated abutment means operated to release said rod for slow vertical movement.

3. In a machine tool, a base, a work support and a tool support on said base, means mounting one of said Supports for movement on said base toward and away from the other of said supports, pressure control feed means connected between said base and said one support to apply a constant force to said one support to move it toward said other support, said feed means comprising an irreversible cam and cam follower device, and rate control mechanism connected to said device to limit the rate of relative movement between the cam and cam follower parts of said device to substantially eliminate momentum effects thereof.

4. In a machine tool, a base, a work support and a tool support on said base, means mounting one of said supports for movement on said base toward and away from the other of said supports, pressure control feed means connected between said base and said one support to apply a constant force to said one support to move it toward said other support, said feed means comprising an irreversible cam and cam follower device, and a resilient member connecting said device to said one support yieldable to prevent attainment of harmful pressures between a tool and work piece carried by said supports.

5. In a machine tool, a base, a work support and a tool support on said base, means mounting one of said supports for movement on said base toward and away from the other of said supports, pressure control feed means connected between said base and said one support to apply a constant force to said one support to move it toward said other support, said feed means comprising a vertically movable cam rod, a friction bushing in which said rod is slidable with frictional resistance variable with lateral force applied between said rod and bushing, a cam surface on said rod inclined at a small angle to its length, and a cam follower engaging said cam and connected to said movable support.

6. In a machine tool, a base, a work support and a tool support on said base, means mounting one of said supports for movement on said base toward and away from the other of said supports, pressure control feed means connected between said base and said one support to apply a constant force to said one support to move it toward said other support, said feed means comprising a vertically movable cam rod, a predetermined weight connected to said cam rod, a friction bushing in which said rod is slidable with frictional resistance variable with lateral force applied between said rod and bushing, a cam surface on said rod inclined at a small angle to its length, and a cam follower engaging said cam and connected to said movable support, the connection between said cam follower and movable support comprising a yieldable spring effective to limit the maximum pressure between a tool and work piece.

7. In amachine tool, a base, a work support and a tool support on said base, means mounting one of said supports for movement on said base toward and away from the other of said supports, pressure control feed means connected between said base and said one support to apply a constant force to said one support to move it toward said other support, said feed means comprising a vertically movable cam rod, a bushing in which said rod is slidable with frictional resistance variable with lateral force appled between said rod and bushing, a cam surface on said rod inclined at a small angle to its length, a rocker body having a cam follower thereon engageable With said cam surface, a second oppositely inclined cam surface on said rod, a second cam follower on said rocker body, means intermediate said cam followers mounting said rocker body for rocking movement, means for moving said cam rod in opposite directions to effect reverse rocking of said body, and means connecting said rocker body to said movable support.

8. In a machine tool, a base, a work support and a tool support on said base, means mounting one of said supports for movement on said base toward and away from the other of said supports, pressure control feed means connected between said base and said one support to apply a constant force to said one support to move it toward said other support, said feed means comprising a vertically movable cam rod, a bushing in which said rod is slidable with frictional resistance variable with lateral force appled between said rod and bushing, a cam surface on said rod inclined at a small angle to its length, a rocker body having a cam follower thereon engageable with said cam surface, a second oppositely inclined cam surface on said rod, a second cam follower on said rocker body, means intermediate said cam followers mounting said rocker body for rocking movement, means for moving said cam rod in opposite directions to effect reverse rocking of said body, and means connecting said rocker body to said movable support, means for limiting downward movement of said rod to a slow rate and for elevating said rod, said last means comprising a movable abutment engageable by said rod.

9. In a gear finishing machine tool, a base, a work support and a tool support on said base, means on said supports mounting a work gear and gearlike tool in mesh, means mounting one of said supports for movement on said base toward and away from the other support, irreversible means for applying a constant predetermined force to said one support in a direction to move it toward said other support, and additional means to provide for movement of said one support away from said other support when the force developed by contact between a tool and work piece exceeds said predetermined force.

10. In a gear finishing machine comprising a base, a rotary work support on said base for a work gear, a rotary tool support on said base for a gear-like tool in mesh with the work gear, and means mounting one of said supports on said base for movement toward and away from the other support, the improvement which comprises pressure control bias means, said bias means comprising a movable cam and cam follower device connected between the base and said movable support to urge said movable support toward the other of said supports, said cam having a cam surface engaged by said cam follower which extends at an angle with respect to the direction of movement of said cam so small as to insure irreversibility of said device, means connected to said cam to apply a constant bias force thereto, said device including a yieldable connection to prevent attainment of dangerous forces if rotation in mesh of the gear and tool requires separation therebetween.

11. Structure as defined in claim 10 which comprises movement control means operatively connected to said movable cam to prevent motion thereof at a rate sufiiciently rapid to develop appreciable inertia.

12. Structure as defined in claim 11 in which said movement control means comprises a movable abutment engaged by said cam, and reversible drive means connected to said abutment.

13. In a gear finishing machine comprising a base, a rotary work support on said base for a work gear, a rotary tool support on said base for a gear-like tool in mesh with the work gear, and means mounting one of said supports on said base for movement toward and away from the other support, the improvement which comprises pressure control bias means, said bias means comprising a movable cam and cam follower device connected between the base and said movable support to urge said movable support toward the other of said supports, said device comprising a friction bushing, a rod slidable in said bushing, means connected to said rod to apply a constant bias thereto in an axial direction, a cam on said rod at one side thereof, and a cam follower engaging said cam and pressing said cam into friction contact with said bushing.

14. Structure as defined in claim 13 in which said device includes a yieldable safety connection operative to a? a yield only at forces greater than developed by moveyield only at forces greater than developed by movement ment of said rod. of said rod.

15. Structure as defined in claim 13 in which said cam comprises a cam surface extending at an irreversible UNITED ATE TENT angle so that separation between said supports is not 5 References Cited in the file of this patent provided for by said carn and cam follower. I 1 559 908 Parson et a1 Nov 3 1925 16. Structure as defined in claim 15 in which said de 2,526,796 Asbridge Oct. 1950 vice includes a yieldable safety connection operative to 

